Turns out RethinkDB is a SSD database to watch in 2011. I’ve known about it for a while but it hasn’t really stood out just yet (I don’t know anyone running it in production).

That said, I’m excited by the potential.

What’s really shocking to me, is that while SSD and flash storage is very exciting, it wasn’t as revolutionary in 2010 as I would have liked to have seen.

I’m not sure why this is… there are people running them at scale but not significantly enough to make them a revolution.

RethinkDB is a MySQL data store optimized for solid state drives. Solid-state drives do away with moving parts and are extremely low-latency. Most database stores are designed for traditional hard drives and assume relatively high-latency. RethinkDB aims to allow database developers to take full advantage of the performance benefits of solid-state drives.

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This is to follow up on my previous post and show the results for MySQL 5.5.8 and Percona Server on the fastest hardware I have in our lab: a Cisco UCS C250 server with 384GB of RAM, powered by a Virident tachIOn 400GB SLC card.

To see different I/O patterns, I used different innodb_buffer_pool_size settings: 13G, 52G, an 144G on a tpcc-mysql workload with 1000W (around 100GB of data). This combination of buffer pool sizes gives us different data/memory ratios (for 13G - an I/O intensive workload, for 52G - half of the data fits into the buffer pool, for 144G - the data all fits into memory). For the cases when the …

As we can see, MySQL 5.5.8 comes with great improvements and scalability fixes. Adding up all the new features, you have a great release. However, there is one area I want to touch on in this post. At Percona, we consider it important not only to have the best peak performance, but also stable and predictable performance. I refer you to Peter's post, Performance Optimization and Six Sigma.

In Percona Server (and actually even before that, in percona-patches builds for 5.0), we added adaptive checkpoint algorithms, and later the InnoDB-plugin included an implementation of  "adaptive flushing". This post shows the differences between them and MySQL.

The post also answers the question of whether we are going to have releases of Percona Server/XtraDB based on the …

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Today's databases are designed for the spinning platter of the hard disk. They take into account that the slowest part of reading data is seeking: physically getting the read head to the part of the disk it needs to be in. But the emergence of cost effective solid state drives (SSD) is changing all those assumptions.

Over the course of 2010, systems designers have been realizing the benefits of using SSDs in data centers, with major IT vendors and companies adopting them. Drivers for SSD adoption …

(Note: The review was done as part of our consulting practice, but is totally independent and fully reflects our opinion)

In my talk on MySQL Conference and Expo 2010 "An Overview of Flash Storage for Databases" I mentioned that most likely there are other players coming soon. I actually was not aware about any real names at that time, it was just a guess, as PCI-E market is really attractive so FusionIO can't stay alone for long time. So I am not surprised to see new card provided by Virident and I was lucky enough to test a pre-production sample Virident tachIOn 400GB SLC card.

I think it will be fair to say that Virident targets where right now FusionIO has a monopoly, and it will finally bring some competition to the market, which I believe is good for …

This run is very similar what I had on Intel SSD X25-M card, but now I use FusionIO 80GB SLC card. I chose this card as smallest available card (and therefore cheapest. On Dell.com you can see it for about $3K). There is also FusionIO IO-Xtreme 80GB card, which is however MLC based and it could be not best choice for FlashCache usage ( as there high write rate on FlashCache for both reading and writing to/from disks, so lifetime could be short).

Also Facebook team released WriteThrough module for FlashCache, which could be good trade-off if you want extra warranty for data consistency and your load is mostly read-bound, so I tested this mode also.

All …

Finally I was able to run PBXT 1.0.11 pre-GA in tpcc-like workload, apparently there was bug with did not allow me to get the result earlier, and I am happy to see that PBXT team managed it.

For initial runs I took tpcc 100 warehouses ( about 10GB of data) which fully fits into memory (32 GB on server),
and compared 1 and 16 users in MySQL-5.1.46/PBXT and Percona Server / XtraDB - 5.1.45-rel10.2. As workload is totally memory based it will show how PBXT scales in CPU-bond cases on 16 cores systems.

As storage system it was Intel SSD X25-M card.

While full results and config are on Wiki:
http://www.percona.com/docs/wiki/benchmark:pbxt:tpcc:start

there are graphs for 1 user:

Previously I covered simple case with FlashCache, when data fits into cache partitions, now I am trying to test when data is bigger than cache.

But before test setup let me address some concern (which I also had). Intel X25-M has a write cache which is not battery backuped, so there is suspect you may have data loss in the case of power outage.
And in the case with FlashCache it would mean you can send your database to trash, as there is no way to recovery from that ( only restore from backup).
I personally did couple of power failure tests and there is article on this topic http://www.anandtech.com/show/2614/10. I did not see any data loss in my tests, and the article says that the write cache "..isn't used for user data because of the risk of data …

I wrote about FlashCache there, and since that I run couple benchmarks, to see what performance benefits we can expect.
For initial tries I took sysbench oltp tests ( read-only and read-write) and case when data fully fits into L2 cache.

I made binaries for FlashCache for CentOS 5.4, kernel 2.6.18-164.15, you can download it from our testing stage. It took some efforts to make binary, you may get my instructions for CentOS on FlashCache-dev mail-list, most likely it will not work for different CentOS / Kernel.

The full results, scripts and settings are on …

Here are the slides and video for my MySQL UC ignite talk on measuring the performance of SSDs.

You can find this talk and other mostly technical material at http://tokutek.com/technology/.

This research was funded in part by the National Science Foundation.